According to release announcement, following are major highlights of this release.

1. A New Method for Packages Update

Better reliabilityEach mirror stores version history, thus allowing either to update from any existing mirror or to create a local mirror.

Updates are fasterThe update tool selects the fastest mirror.Update configuration defaults to parallel fetching and installation. Revdep-rebuild will not be called by cl-update unless enabled explicitly.

A higher level of testingAll binaries are tested on the testing mirror before being committed to the master.

Less traffic consumptionPortage will not be synchronized if no updates are available.

2. Common binary repos

Distribution profiles were unified. You are free to choose between three brand new flavours, each with USE flags adapted to different needs. Over 2500 popular packages come as binaries.

For more highlights and information, see complete release announcement here.